The present invention relates to a remote control system for telecommunications links. The remote control of a link or connection is understood to mean any operation of controlling at a distance the operation of said link involving transmissions of orders and/or information with the object, for example, of locating defective amplifiers or repeaters or monitoring such members, or for locating a transmission cable break, etc. The invention can be used in telecommunications in the case of remotely supplied links.
In telecommunications systems using a physical support (cables with symmetrical or coaxial pairs) the amplifiers of analog links or the regenerative repeaters of digital links are remotely supplied. The transmission of analog or digital signals only occupies the frequency spectrum as from a lower cut-off frequency, leaving free a channel passing from a continuous state to the said cut-off frequency. Thus, in addition to the remote supply current, this channel can transmit a low frequency system. In digital transmission systems, this channel is used for the remote location of defective repeaters or the remote continuous monitoring of the operation of such repeaters.